Starting relay for monophase motors



Feb. 11, 1964 v` RlNl 3,121,150

STARTING RELAY FoR MoNoPHAsE MoToRs `Filed Maron 21, 1962 INVENTOR. /ncunro 2in1' United States Patent Oiice 3,l2l,l5ii Patented Feb. 11, 1964 STARTING RELAY FUR MONOPHASE MTORS Vincenzo Rini, Milan, italy, assigner, by mesne assignments, to AMF Overseas Corporation, Vernier, Geneva,

Switzerland Y Filed Mar. 21, 1962, Ser. No. 181,292 Claims priority, application Italy Mar. 30, 1961 6 Claims. (Cl. Zitti- 111) This invention is concerned with starting relays of the type including switch means designed to be connected to the starting circuit of a monophase electric motor, a coil designed to be connected in the service circuit of said motor, and a vertica-lly movable magnetizable core in the magnetic field of said coil, the said switch means comprising a movable contact assembly responsive to the movements of said core upon variation of said magnetic field.

More particularly, the present invention is concerned with a relay of the above type and adapted to be made use of for starting of monophase electric motors of refrigerator implements'and similar applications including a monophase electric motor requiring a switching device for switching on a motor starter winding during the starting and acceleration steps of the device, i.e. while the current absorption in the motor regular service winding is over a predetermined service value and such to increase the energy of the said magnetic field to the evel required for upwardly mov-ing the said magnetizable core and thereby causing the said switch means to close the starting circuit of the motor. n

Such starting relays or starters are generally constructed, as it is known to those skilled in the art to which this invention appertains, as small sized and economically manufactured units comprising a structure of electrically insulating material having an upper space for housing a Contact assembly and a vertically arranged bobbin core portion, a coil wound about said bobbin core and a cylindrical space in the vertical axis of said bobbin core. The said contact assembly includes a pair of downwardly facing stationary contacts and a movable conductor element having a pair of contacts complementa-ry to the said stationary contacts and movable into and out of contact relation therewith upon upward and respectively downward movement of the element toward and away from the stationary contacts. A cylindrical magnetizable core is arranged `for vertical movement in the said cylindrical space and a small coil spring is arranged between said core and said movable conductor element in abutting relationship therewith for upwardly urging said conductor element as said magnetizabfle core is magnetically upwardly urged.

The above described essential components of the said relay are relatively positioned and sized so that the said magnetizable core may be upwardly urged only as the current absorption of the service winding of the motor and therefore the i'low of the current in the said relay coil is over a predetermined value, corresponding to the starting and acceleration current absorption, so that the said motor starting winding of the motor may be energized as the motor starts and accelerates.

The above `considered devices are however subject to certain serious objections, either in View of prompt selfaction and in View of `du-rableness thereof. It has been ctound that the abruptly upwardly urged magnetizable core of such relay sometimes bounces downwardly back thus causing a temporary breaking olf of the starting circuit, and then causing a new abrupt upward motion of the movable parts. -In such occurrence the relay behaves frantically and the starting and acceleration of the motor is seriously prejudiced. The repeating scintillation occurring between the stationary and movable contacts damages such contacts and the same motor may be seriously injured too by the resulting pulsing feeding of its starting winding.

Such known relays are similarly subject to frantically behave also when subject tovibrate, namely when secured to implements including reciprocated components, such as a pump of a refrigerator unit and the like.

It is therefore a principal object to provide a relay of the type above considered, which is improved so that it is not subjected to the said and other known objections common to currently produced devices.

According to the invention, it has been surprisingly Afound that, lby providing and arranging a magnetizable means about the said magnetizable core housing space at the level at which said core is carried by the said coils magnetic field as the current absorption attains its said starting and acceleration values, an ancillary magnetic circuit is formed across said magnetizable core and means, which is capable to firmly maintain said core at said levelwwhereby a continuous contact relation is ensured between the contacts of said contact assembly for proper and safe starting and acceleration of the motor.

According to a more particular feature of this invention, the said magnetizable means consists of two spaced and superimposed iron made ring elements embedded in the wall of said bobbing core of the relay coil and located at the level of the upper and respectively of the lower face of the said cylindrical magnetizable core as said latter core is at its upper position at the level of said coil.

The novel features of the present invention are set forth in the appended claims. The present invention however, both as to its construction and operation, together with further advantages and objects thereof, will be best understood by way of illustration and example by the following detailed description of a preferred form of embodiment thereof when taken in conjunction with the accompanying drawings, form-ing an essential component of this disclosure, and wherein:

FIGURE 1 illustrates in enlarged scale and in vertical sectional eleva-tion la preferred embodiment of the relay, when in its off condition;

FIGURE 2 is a transversal sectional view of the same,

taken in the plane indicated at 2 2 in FIG. l; and

FIGURE 3 is a View similar to FIG. 1, wherein the relay is shown as at its on condition, and wherein the new combination and arrangement o-f parts of the invention are evidenced in respect with the remaining components and arrangement appeutaining to current knowledge ofthe art.

vReferring now to the drawing, wherein like reference numerals refer to like parts and components throughout the several gures:

According to current knowledge of the art, the relay unit includes a relay body 10 of electrically insulating material and having lan upper portion and a lower portion. The said upper portion, provided with a cover plate 11, is designed to house the contact assembly embodying the switch means designed to be connected in the circuit of the starting winding of the motor (not shown). Said contact assembly comprises a pair of down-facing stationary contacts 12 connected to terminals 13 for the said connection of the device to the said starting circuit.

Said contact assembly further comprises a movable conductor element 1S to which a pair of movable contacts 14 is secured, the said movable contacts being complementary to said stationary contacts 12 and adapted for abutment thereon as said movable element 1S is upwardly urged, as shown in FIG. 3. The upward motion of said movable element is caused by an upward movement, of greater amplitude, of a magnetizable cylindrical core 16 vertically movable and guidely arranged into a vertical cylindrical space i7 in the lower portion of said relay body it?, which embodies a bobbin core for a coil 18 designed to be connected in the service winding circuit of the motor.

An upwardly directed small rod i9 is coaxially arranged and secured to the said magnetizable core lo and slidably passes through the said movable conductor element l5.l A small coil spring Ztl is located about said rod i9 between said core lo and said element vi5 in abutting relationship therewith, so that as said core lo is moved by the said coil 18, which acts as a solenoid, the said conductor element l' is springly upwardly urged for putting the said complementary contacts ll2 and ld in their contact relation and therefore closing the starting circuit of the motor between the terminals i3.

The movable assembly including components ld, 15, lo, i@ and 24B is so weighted in relation wtih the moving power or magnetic force of solenoid coil itl that, according to the art, the said magnetizable core lo can be upwardly moved only when the current iiowing in the said coil 18 attains a predetermined value, corresponding to the absorption of the motor service winding as the motor is started and encounters the overload due to acceleration o'f the correlated driven parts of the refrigerator unit or other motor driven implement.

According tothe invention, in the electrically insulating wall of said cylindrical space ll7 there are embedded two magnetizable iron made rings Zit and ZZ, the said rings being located, as particularly shown in FIG. 3, at the level of upper portion and of lower portion of said magnetizable core ltd, when such core is set at its upper position upon the production of electromagnetic force by the said solenoid coil iii.

The said components 21 and 22, as being made of magnetizable material, actuate a magnetizable system set at the level of the said core ,to when at its upper level (FIG. 3) in the magnetic field of coil i8 and, upon raising of said core lo at its said upper level, a magnetic flow is therefore caused to be produced and closed through the said interrupted rings 2l and 22 and the said core 16x, the path of said magnetic fiow being diagrammatically indicated by dashed lines in FlG. 3, in any vertical plane including the relay axis.

llt has been surprisingly found that .the above described provision of the said magnetizable system may fully remove the above said objections to which the currently produced relays are subject. in the device of the invention, as the said magnetizable core llo reaches its upper position of FIG. 3 said core lo is firmly kept or stabilized at its said upper position by the magnetic force exerted by the said closed magnetic circuit of FIG. 3, which in other words acts as a booster in respect with the magnetic eld of the solenoid coil itt.

The said components 2l `and ZZ of the said magnetizable system are advantageously embedded within the bobbin core walls to avoid any direct contact between said components and said core lo and therefore to prevent phenomena of adhesion and excess of attractive force between said components and core, which might prevent or disturb the prompt dropping of core lo at its lov/er position of FIG. l, as the current value in coil l@ drops upon complction of the starting step of the motor, for de-energization of the starting winding of the motor.

in the actual construction of the device of the invention, the said interrupted rings 2d and 22 may be advantageously located between the boobn core wall forming portion of relay body lll and an inner skirt 2dof electrically insulating material, located inside said portion and embodying the inner face of the said space 17. The said inner skirt Zd may be advantageously formed by die-casting a known thermosetting material about said rings and then by manufacturing the whole relay body itil by die-casting like or differing thermosetting material about the said preliminarily produced subassembly including said components 2l, ZZand It is Itherefore believed to be evident that the presen-t invention provides a plurality of advantageous features, and it will be understood that each of the new features described and shown and any combination thereof may aiso dnd useful application in other relay implements differing from the one described.

Without fur` ier consideration, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt it for other applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of this invention and, therefore, such adaptation should and are intended to be comprehended within the spirit and meaning of this invention as above set forth and defined in and by the appended claims.

Having thus described the invention, what l claim as new and desire to have protected by Letters Patent of the United States of America is:

l. A relay arrangement comprising, in combination,

housing means;

fixed `Contact means fixediy mounted in said housing means; slidable magnetiaable core means slidably mounted in said housing means, said magnetizable core means having an axis, an upper end and a lower end;

contact means mounted on said magnetizable core means;

energizing means for siidably moving said magnetizable core means along its axis to an operative position in Iwhich said contact means abut said fixed contact means, said energizing means comprising magnetic winding means coaxially positioned in operative proximity with said magnetizable core means; and

stabilizing means for stabilizing said magnetizable core means in its operative position, saidv stabilizing means comprising a pair of spaced magnetizable rings axially positioned with said magnetizable core means in said housing means in operative proximity with said magnetizable core means, one of said magnetizable rings being positioned at substantially the level of the upper end of said magnetizable core means in its operative position and the other of said magnetizable rings being positioned at substantially theV level of the lower end of said magnetizable core means in its operative position.

2. A relay arrangement comprising, in combination,

a housing means;

fixed `Contact means iixedly mounted in said housing means;

slidable magnetizable core means slidably mounted in said housing means, said magnetizable core means having an axis, an upper end, a lower end and a length extending from said upper end to said lower end;

contact means mounted on said magnetizable core means;

energizing means for slidably moving said magnetizable core means along its axis to an operative position in which said Contact means abut said iixed contact means, said energizing means comprising magnetic ywinding means coaxially positioned in operative proximity with said magnetizable core means; and stabilizing means for stabilizing said magnetizable core means in its operative position, said stabilizing means comprising a pair of magnetizable rings spaced from each other a distance equal to the length of said magnetizable core means and coaxiaily positioned with said magnetizable core means in said housing.

means in operative proximity with said magnetizable core means, one of said magnetizable rings being positioned at substantially the level of the upper end of said magnetizable core means in its operative position and the other of said magnetizable rings being positioned at substantially the level of the lower end of said magnetizable core means in its operative position.

3. A relay arrangement comprising, in combination,

housing means;

tixed contact means iixedly mounted in said housing means;

slidable magnetizable core means slidably mounted in said housing means, said magnetizable core means having an axis, an upper end and a lower end;

contact means mounted on said magnetizable core means;

energizing means for slidably moving said magnetizable core means along its axis to an operative position in which said contact means abut iixed contact means, said energizing means comprising magnetic winding means coaxially positioned in operative proximity with said magnetizable core means; and

stabilizing means for stabilizing said magnetizable core means in its operative position, said stabilizing means comprising a pair of spaced magnetizable rings coaxially positioned with said magnetizable core means in said housing means between said magnetizable core means and saidI energizing means in operative proximity with said magnetizable core means, one of said magnetizable rings being positioned at substantially the level of the upper end of said magnetizable core means in its operative position and the other of said magnetizable rings being positioned at substantially the level of the lower end of said magnetizable core means in its operative position.

4. A relay arrangement comprising, in combination,

non-magnetic housing means;

xed contact means iixedly mounted in said housing means;

slidable magnetizable core means slidably mounted in said housing means, said magnetizable core means having an axis, an upper end and a lower end;

contact means mounted on said magnetizable core means;

energizing means for slidably moving said magnetizable core means along its axis to an operative position in which said contact means .abut said fixed Contact means, said energizing means comprising magnetic winding means coaxially positioned in operative proximity with said magnetizable core means; yand stabilizing means for stabilizing said magnetizable core means in its operative position, said stabilizing means comprising a pair of spaced magnetizable rings coaxially positioned with said magnetizable core means in operative proximity with said magnetizable core means and embedded in said housing means, one of said magnetizable rings being positioned at substantially the level of the upper end of said magnetizable core means in its operative position and the other of said magnetizable rings being positioned at substantially the level of the lower end of said magnetizable core means in its operative position.

5 A relay arrangement comprising, in combination,

housing means;

fixed contact means ixedly mounted in said housing means;

slidable magnetizable core means slidably mounted in said housing means, said magnetizable core means having an axis, an upper end and a lower end;

movable contact means spring mounted on said magnetizable core means;

energizing means lfor `slidably moving said magnetizable core means along its axis to an operative position in which said Contact means abut said iixed contact means, said energizing means comprising magnetic winding means coaxially positioned in operative proximity with said magnetizable core means; and

stabilizing means for stabilizing said magnetizable core means in its operative position, said stabilizing means comprising a pair of spaced magnetizable rings coaxially positioned with said magnetizable core means in said housing means in operative proximity with said magnetizable core means, one of said magnetizable rings being positioned at substantially the level of the upper end of said magnetizable core means in its operative position and the other of said magnetizable rings being positioned at substantially the level of the lower end of said magnetizable core means in its operative position.

6. A relay arrangement comprising, in combination,

non-magnetic housing means;

tixed contac-t means iixedly mounted in said housing means;

slidable magnetizable core means slidably mounted in said housing means, said magnetizable core means having an axis, an upper end, a lower end and a length extending from said upper end to said lower end;

movable contact means spring mounted on said magnetizable core means;

energizing means for slidably moving said magnetizable core means along its axis to an operative position in which said movable Contact means abut said fixed contact means, said energizing means comprising magnetic Winding means coaxially positioned in operative proximity with said magnetizable core means; and

stabilizing means for stabilizing said magnetizable core means in its operative position, said stabilizing means comprising a pair of magnetizable `rings spaced from each other a distance equal to the length of said magnetizable core means coaxially positioned with said magnetizable core means in operative proximity with said magnetizable core means and embedded in said housing means between said magnetizable core means and said energizing means, one of said magnetizable rings being positioned at substantially the level of the upper end of said magnetizable core means in its operative position and the other of said magnetizable rings being positioned at substantially the level of the lower end of said magnetizable core means in its operative position.

References Cited in the le of this patent UNITED STATES PATENTS 2,425,038 Lear Aug. 5, 1947 2,488,441 Shaw Nov. 15, 1949 2,871,422 lessee ian. 27, 1959 2,992,304 Andrews July `11, 1961 3,022,450 Chase Feb. 20', 1962 3,040,217 Conrad lune 19, 1962 

1. A RELAY ARRANGEMENT COMPRISING, IN COMBINATION, HOUSING MEANS; FIXED CONTACT MEANS FIXEDLY MOUNTED IN SAID HOUSING MEANS; SLIDABLE MAGNETIZABLE CORE MEANS SLIDABLY MOUNTED IN SAID HOUSING MEANS, SAID MAGNETIZABLE CORE MEANS HAVING AN AXIS, AN UPPER END AND A LOWER END; CONTACT MEANS MOUNTED ON SAID MAGNETIZABLE CORE MEANS; ENERGIZING MEANS FOR SLIDABLY MOVING SAID MAGNETIZABLE CORE MEANS ALONG ITS AXIS TO AN OPERATIVE POSITION IN WHICH SAID CONTACT MEANS ABUT SAID FIXED CONTACT MEANS, SAID ENERGIZING MEANS COMPRISING MAGNETIC WINDING MEANS COAXIALLY POSITIONED IN OPERATIVE PROXIMITY WITH SAID MAGNETIZABLE CORE MEANS; AND STABILIZING MEANS FOR STABILIZING SAID MAGNETIZABLE CORE MEANS IN ITS OPERATIVE POSITION, SAID STABILIZING MEANS COMPRISING A PAIR OF SPACED MAGNETIZABLE RINGS COAXIALLY POSITIONED WITH SAID MAGNETIZABLE CORE MEANS IN SAID HOUSING MEANS IN OPERATIVE PROXIMITY WITH SAID MAGNETIZABLE CORE MEANS, ONE OF SAID MAGNETIZABLE RINGS BEING POSITIONED AT SUBSTANTIALLY THE LEVEL OF THE UPPER END OF SAID MAGNETIZABLE CORE MEANS IN ITS OPERATIVE POSITION AND THE OTHER OF SAID MAGNETIZABLE RINGS BEING POSITIONED AT SUBSTANTIALLY THE LEVEL OF THE LOWER END OF SAID MAGNETIZABLE CORE MEANS IN ITS OPERATIVE POSITION. 